U.S. patent number 11,359,595 [Application Number 17/040,296] was granted by the patent office on 2022-06-14 for runner for a hydraulic turbine or pump and method of manufacturing.
This patent grant is currently assigned to Voith Patent GmbH. The grantee listed for this patent is VOITH PATENT GMBH. Invention is credited to Stuart Coulson, Jason Foust, Brandon Harmer, Jianbo Jiang, Steven McHale, Jesse Zoll.
United States Patent |
11,359,595 |
Coulson , et al. |
June 14, 2022 |
Runner for a hydraulic turbine or pump and method of
manufacturing
Abstract
A runner for a hydraulic turbine or pump includes a plurality of
blades, each blade being defined by a pressure surface, an
oppositely facing suction surface, a leading edge and a spaced
apart trailing edge. At least one blade has a device for supplying
a flow of oxygen containing gas to the trailing edge of at least
one of the blades. The profile of the suction side surface of the
blade along a cross section through a point P1 and a point P2 is
concave. The point P1 is located on the suction side surface of the
trailing edge where an opening is located, the point P2 is spaced
apart from the point P1 by less than 3% of the runner outlet
diameter D and the point P2 is located upstream of the point P1 on
a line perpendicular to the trailing edge starting at the point
P1.
Inventors: |
Coulson; Stuart (Seven Valleys,
PA), Foust; Jason (Jacobus, PA), Zoll; Jesse
(Mountville, PA), McHale; Steven (Harrisburg, PA), Jiang;
Jianbo (York, PA), Harmer; Brandon (York, PA) |
Applicant: |
Name |
City |
State |
Country |
Type |
VOITH PATENT GMBH |
Heidenheim |
N/A |
DE |
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Assignee: |
Voith Patent GmbH (Heidenheim,
DE)
|
Family
ID: |
1000006370995 |
Appl.
No.: |
17/040,296 |
Filed: |
February 28, 2019 |
PCT
Filed: |
February 28, 2019 |
PCT No.: |
PCT/EP2019/054937 |
371(c)(1),(2),(4) Date: |
September 22, 2020 |
PCT
Pub. No.: |
WO2019/179742 |
PCT
Pub. Date: |
September 26, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20210017948 A1 |
Jan 21, 2021 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62697736 |
Jul 13, 2018 |
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62646589 |
Mar 22, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F03B
3/121 (20130101); F03B 11/002 (20130101); F03B
3/183 (20130101); F05D 2240/24 (20130101); F05D
2240/30 (20130101); F05B 2260/96 (20130101) |
Current International
Class: |
F03B
3/12 (20060101); F03B 3/18 (20060101); F03B
11/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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106471245 |
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Mar 2017 |
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CN |
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2011137407 |
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Jul 2011 |
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JP |
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2017108120 |
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Jun 2017 |
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WO |
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Primary Examiner: Lee, Jr.; Woody A
Assistant Examiner: Wong; Elton K
Attorney, Agent or Firm: Greenberg; Laurence A. Stemer;
Werner H. Locher; Ralph E.
Claims
The invention claimed is:
1. A runner for a hydraulic turbine or pump, the runner comprising:
a plurality of blades, each blade defined by a pressure side
surface, an oppositely facing suction side surface, a leading edge
and a spaced apart trailing edge; at least one of said blades
having a device for supplying a flow of oxygen containing gas to
said trailing edge of said at least one blade, said device
including a gas inlet aperture, a gas passage and at least one
opening in said trailing edge to admit gas out of said gas passage
to a passing fluid during operation of the runner; said suction
side surface of said at least one blade having a concave profile
along a cross section through a point P1 and a point P2, said point
P1 being located on said suction side surface of said trailing edge
at said at least one opening, said point P2 being spaced apart from
said point P1 by less than 3% of a runner outlet diameter D and
said point P2 being located upstream of said point P1 on a line
perpendicular to said trailing edge starting at said point P1.
2. The runner according to claim 1, wherein a first normal vector
on said suction side surface located at said point P1 and a second
normal vector on said suction side surface located at said point P2
enclose an angle of at least 2 degrees.
3. The runner according to claim 1, wherein the runner is an axial
flow runner including a hub and said plurality of blades extending
from said hub at circumferentially spaced intervals.
4. The runner according to claim 1, wherein the runner is a Francis
turbine including a crown, a band and said plurality of blades
extending from said crown to said band at circumferentially spaced
intervals.
5. The runner according to claim 1, wherein said pressure side
surface extends further than said suction side surface measured
from said leading edge along a section camberline in a region of
said opening.
6. A method of manufacturing a runner, the method comprising:
providing the runner according to claim 1 including said at least
one blade having said trailing edge and said gas passage; providing
a piece of material; and connecting the piece of material to said
trailing edge of said at least one blade.
7. The method according to claim 6, which further comprises forming
said at least one opening in said piece of material before
connecting said piece of material to said at least one blade, and
connecting said at least one opening to said gas passage of said
blade after connecting said piece of material to said trailing edge
of said at least one blade.
8. The method according to claim 6, which further comprises forming
said at least one opening in said piece of material after
connecting said piece of material to said at least one blade, and
connecting said at least one opening to said gas passage of said at
least one blade after connecting said piece of material to said
trailing edge of said at least one blade.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to hydroelectric turbine or
pump installations. More particularly, this invention pertains to
hydroelectric installations with means for enhancing the level of
dissolved gas in water passing through the turbine or pump.
A significant environmental problem for many hydroelectric
facilities is the water quality of discharges. Various attempts
have been made to enhance the level of dissolved oxygen in
discharged water of hydroelectric installations. For example, U.S.
Pat. No. 5,924,842 to Beyer, James R. discloses a runner for a
Francis turbine comprising a crown; a band substantially concentric
with the crown; and a plurality of blades extending between crown
and the band at spaced intervals along the crown, each blade
fixedly secured to the crown at an inner edge and to the band at a
distal outer edge, each blade having a water directing surface
defined by a pressure side, an opposite facing suction side, a
leading edge and a spaced apart trailing edge, at least one of the
blades including: a leading edge blade portion having a rear edge
in which a first slot is machined along at least a portion of the
rear edge; a trailing portion having a front edge in which a second
slot is machined along at least a portion of the front edge;
wherein the trailing portion is fixedly secured to the leading
blade portion along the front edge and the rear edge, respectively,
so that the first and second channels cooperate to form an integral
passage in the at least one of the blades; and means for
discharging an oxygen containing gas from the integral passage to a
location adjacent the trailing edge.
The objective of the mentioned state of the art is to increase the
level of dissolved oxygen downstream of the turbine or pump by
introducing an oxygen containing gas into the water passing through
the unit. The amount of gas introduced into the water passing
through the unit depends on the pressure conditions on the
low-pressure side of the runner. For example when the tailwater
level rises and therefore the backpressure is increased, the
aeration capability of the prior art designs may become
ineffective. It is common at hydropower plants that the downstream
level (often referred to as tail water level) rises as more flow is
passed through the turbine(s) of the hydro plant or if flow is
released over an adjacent spillway. The resulting higher tail water
level increases the pressure at the outlet of the turbine. In
aerating turbines, the source of the oxygen containing gas is often
atmospheric air in the hydro plant. As the pressure downstream of
the turbine runner increases, the flow of atmospheric air is
reduced or even stopped due to insufficient pressure
differential.
SUMMARY OF THE INVENTION
The objective of the present invention is to increase the level of
dissolved oxygen downstream of the turbine or pump over the level
of dissolved oxygen achieved by state of the art when backpressure
increases.
The present invention provides a runner of a hydraulic turbine or
pump which is capable of maintaining high levels of dissolved
oxygen when backpressure increases.
The problem is solved by a runner for a hydraulic turbine or pump,
comprising a plurality of blades, each blade being defined by a
pressure surface, an oppositely facing suction surface, a leading
edge and a spaced apart trailing edge, at least one of the blades
having a device for supplying a flow of oxygen containing gas to
the trailing edge of the same blade, the device includes a gas
inlet aperture, a gas passage and one or more openings in the
trailing edge surface to admit gas out of the gas passage to the
passing fluid during operation of the runner, the profile of the
suctions side surface of the blade along a cross section through a
point P1 and a point P2 is concave, the point P1 is located on the
suction side surface of the trailing edge where an opening is
located and point the P2 is spaced apart from the point P1 by less
than 3% of the runner outlet diameter D and the point P2 is located
upstream of the point P1 on a line perpendicular to the trailing
edge starting at the point P1. Other favorable implementations of
the invention are disclosed in the depended claims. A method for
manufacturing a runner according the present invention is disclosed
in the independent method claim. Other favorable implementations of
the method for manufacturing are disclosed in the depended claims
thereof.
The inventors have recognized that the problem can be solved by
altering the geometry near the trailing edge of the runner to
create a local drop in pressure on the trailing edge surface. The
present invention also increases the size of the wake downstream of
the trailing edge to provide a path for the airflow through the
wake into the main flow. This results in significantly higher mass
flow of air into the main flow at higher tail water levels where
the prior art became less effective or ineffective. Combining this
higher mass flow of air with the main flow results in higher
dissolved oxygen levels.
The invention will hereinafter be described in conjunction with the
appended drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a cross-sectional view of an axial type runner according
to an embodiment of a runner of the present invention;
FIG. 2 is a cross-sectional view of a Francis type runner according
to an embodiment of a runner of the present invention;
FIG. 3 is a cross-sectional view of a Francis type runner according
to another embodiment of a runner of the present invention;
FIG. 4 is a cross-sectional view of a Francis type runner according
to another embodiment of a runner of the present invention;
FIG. 5 shows cross-sectional views of a Francis and an axial type
runner defining the outlet diameter;
FIG. 6 is a cross-sectional view along A-A of a runner blade;
FIG. 7 is an enlarged view of the trailing edge according to the
cross-sectional view of FIG. 5 according to the prior art;
FIG. 8 is an enlarged view of the trailing edge according to the
cross-sectional view of FIG. 5 according to another embodiment of
the prior art;
FIG. 9 is an enlarged view of the trailing edge according to the
cross-sectional view of FIG. 5 according to the present
invention;
FIG. 10 is an enlarged view of the trailing edge according to the
cross-sectional view of FIG. 5 according to another embodiment of
the present invention;
FIG. 11 is an enlarged view of the trailing edge according to the
cross-sectional view of FIG. 5 according to another embodiment of
the present invention;
FIG. 12 is a cross-sectional view along B-B of a runner blade;
FIG. 13 shows two enlarged cross-sectional views of the trailing
edge according to another embodiment of the present invention;
FIG. 14 shows the flow diagram of a method of manufacturing a
runner according the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 displays schematically a cross-sectional view of an axial
type runner. The runner hub is designated as 1 (only the right side
is shown completely). A runner blade designated as 2 extends from
the hub 1. The blade 2 has a leading edge 3 and a trailing edge 4
meaning that the fluid entering the runner flows from the leading
edge 3 towards the trailing edge 4. The fluid flow is divided by
the blade 2 whereas one side of the blade 2 forms the pressure
surface and the other side the suction surface. At least one blade
2 contains a gas passage, which is designated as 5. The gas passage
5 comprises a gas inlet aperture designated as 6. At the trailing
edge 4 the gas passage 5 forms an opening designated as 7. The gas
inlet aperture 6 is located in the runner hub 1. The arrows are
indicating the gas flow.
FIG. 2 displays schematically a cross-sectional view of a Francis
type runner. The runner crown is designated as 11 (only the right
side is shown completely). A runner blade designated as 2 extends
between the crown 11 and the band designated as 12. The blade 2 has
a leading edge 3 and a trailing edge 4 meaning that the fluid
entering the runner flows from the leading edge 3 towards the
trailing edge 4. The water flow is divided by the blade 2 whereas
one side of the blade 2 forms the pressure surface and the other
side the suction surface. At least one blade 2 contains a gas
passage, which is designated as 5. The gas passage 5 comprises a
gas inlet aperture designated as 6. At the trailing edge 4 the gas
passage 5 forms an opening designated as 7. The gas inlet aperture
6 is located in the runner crown 11. The arrows are indicating the
gas flow.
FIG. 3 displays schematically a cross-sectional view of a Francis
type runner. The designations are the same as in FIG. 2. The gas
passage 5 is differently shaped and forms a number of openings at
the trailing edge 4 of the blade 2, each of the openings being
designated as 7.
FIG. 4 displays schematically a cross-sectional view of a Francis
type runner. The designations are the same as in FIG. 2. The gas
passage 5 is differently shaped. FIG. 4 shows two dashed lines A-A
and B-B which will be used in the cross-sectional views in the
following figures. The line A-A contains a part of the trailing
edge 4 where an opening 7 of the gas passage 5 is located, whereas
the line B-B contains a part of the trailing edge 4 where no
opening 7 of the gas passage is located. Both lines A-A and B-B are
orientated perpendicular to the trailing edge 4. Analog lines can
be defined for an axial type runner according to FIG. 1.
FIG. 5 shows in the upper part a cross-sectional view of a Francis
type runner and in the lower part a cross-sectional view of an
axial type runner. In each of the views, the outlet diameter of the
runner is designated as D.
FIG. 6 is a cross-sectional view of a runner blade 2 along A-A
according to FIG. 4. The blade 2 can be part of a Francis type
runner or an axial type runner. The same holds for all following
figures. The gas passage is designated as 5 and forms an opening at
the trailing edge 4 which is designated as 7. The pressure side
surface of the blade 2 is designated as 13 and the suction side
surface of the blade 2 is designated as 14.
FIG. 7 shows a portion of the view according to FIG. 6 near the
trailing edge 4 according to the prior art. The point designated as
P1 is located on the suction side surface 14 of the trailing edge
4. The point designated as P2 is located on the suction side
surface 14 of the blade 2. The distance between point P1 and point
P2 is less than 3% of the runner outlet diameter D measured in the
direction perpendicular to the trailing edge 4. The arrows are
indicating the normal vectors on the suction side surface 14 of the
blade 2, whereas the normal vector designated as N1 is located at
point P1 and the normal vector designated as N2 is located at point
P2. According to the prior art the profile of the suction side
surface 14 between the points P1 and P2 is straight or slightly
convex meaning that the orientations of the normal vectors N1 and
N2 are the same (or differing only very little) or are pointing
away from each other.
FIG. 8 shows a similar portion of the blade 2 as FIG. 7 according
to another embodiment of the prior art. The only difference to FIG.
7 is that the pressure side 13 of the blade 2 extends further as
the suction side 14 in the direction to the trailing edge 4 of the
blade 2.
FIG. 9 shows a similar portion of the blade 2 as FIG. 7 according
to a first embodiment of the present invention. The designations
are as usual. According to the present invention, the profile of
the suction side surface 14 between the points P1 and P2 is
concave.
This special geometry near the runner trailing edge has not been
applied in the hydro industry since it would normally result in
higher dynamic loading on the runner blades due to the resulting
increased strength of von Karman vortices. The inventors have
realized that this problem can however be overcome since the flow
of gas through the openings at the trailing edge is mitigating the
formation of the vortices.
FIG. 10 shows another embodiment of the present invention. The
difference to the embodiment of FIG. 9 is that the pressure side
surface 13 near the trailing edge 4 is not straight as in FIG. 9
but concave.
FIG. 11 shows another embodiment of the present invention. The
difference to the embodiments of FIGS. 9 and 10 is that the
pressure side surface 13 near the trailing edge 4 is convex.
The inventors have realized that the positive effect of the
invention increases, if the profile of the suction side surface 14
between the points P1 and P2 is concave and the angle between the
normal vectors N1 and N2 is at least 2 degrees. Because the profile
between P1 and P2 is concave, it is clear that the vectors N1 and
N2 are pointing towards each other.
FIG. 12 is a cross-sectional view of a runner blade 2 along B-B
according to FIG. 4.
FIG. 13 shows two enlarged cross-sectional views of the trailing
edge 4 according to another embodiment of the present invention at
different portions of the trailing edge 4. The upper part of FIG.
13 shows a portion of the trailing edge 4 where no opening 7 of the
gas passage 5 is located (B-B) and the lower part of FIG. 13 shows
a portion of the trailing edge 4 where an opening 7 of the gas
passage 5 is located (A-A). The special geometry near the trailing
edge 4 according to the present invention is achieved by connecting
an additional piece of material to the trailing edge 4 of a blade 2
having a conventional shape. The additional piece of material is
designated by 15. In this way a `new` trailing edge 4 is formed by
additional piece of material 15. The lower part of FIG. 13 shows
that the gas passage 5 intersects the piece of additional material
15 in the region where an opening 7 is located. The embodiment
according to FIG. 13 is easy to manufacture and can be used to
apply the present invention to an existing runner aerated according
to the prior art. The additional piece of material 15 can be made
of steel or any other suited material.
The inventors disclose a method for manufacturing a runner
according to the present invention, which is cost-effective and can
be applied to an existing aerated runner made according to the
prior art. However, the manufacturing of a runner according to the
present invention is not restricted to the hereafter-disclosed
method, but can be performed using any other suited known
method.
FIG. 14 shows the flow diagram of a method of manufacturing a
runner according the present invention. The method comprises a step
designated by V1 in which a piece of material 15 and a runner blade
2 with a trailing edge 4 and a gas passage 5 are provided. The
method comprises a step designated by V2 in which the piece of
material 15 is connected to the trailing edge 4 of the runner blade
2 e.g. by welding or gluing.
The runner blade 2 in step V1 can be separate or can already be
integrated in a mechanical subgroup together with other blades 2
and other parts like a hub 1, a crown 11 and/or a band 12.
Either step V1 or step V2 can comprise the application of an
opening 7 to the piece of material 15 in a way that the opening 7
connects to the gas passage 5 of the blade 2 after step V2 has been
accomplished. With other words the opening 7 can be applied to the
piece of material 15 either before or after it has been connected
to the blade 2.
The above-described embodiments of the present invention can be
combined with the geometry of the trailing edge shown in FIG. 8
viz. that the pressure side 13 of the blade 2 extends further as
the suction side 14 in the direction to the trailing edge 4 of the
blade 2.
The present invention is not restricted to the use of atmospheric
air for aeration of the runner but can also be beneficial when
using compressed oxygen-comprising gas by reducing the required
overpressure and thus saving cost of operation.
* * * * *